Breeder focuses on resistance

Delbard was the first nursery in France to breed disease-resistant apples.

Dec 1, 2008

Delbard Nursery uses tissue culture to produce up to 1.5 million rootstocks each year.

Delbard Nursery is quick to adopt new technology. It was the first to establish a tissue culture laboratory for propagation in France, and it is now experimenting with regenesis, a technique to create new genetic material. On the retail side, the nursery is making a mark with its "W" fruit trees that are consumer-friendly, already trained, and are ready for production.

Delbard Nursery dates back more than 70 years to when George Delbard began breeding fruit trees at his family farm in central France’s Malicorne area. Fifty years ago, he added roses, dahlias, and other flowers to his breeding work.

Grandson Arnaud Delbard has continued the business of breeding and developing fruit and rose selections, expanding the operation to include the production of nursery stock for commercial growers as well as 40 retail garden centers. The nursery covers 600 hectares (about 1,500 acres) of greenhouses and field plantings. Land is rotated in a three-year cycle so that about 500 acres are always in production. A number of international partnerships have been developed to globalize the selection and evaluation process of new varieties. Cutting edge

Tissue culture has been the backbone of Delbard’s rootstock propagation for both fruit and roses. In the early 1980s, they began using fragments of stems and green tissue of certified virus-free mother stock to grow plant material in vitro. The clonal propagated material is identical to the mother stock or tissue that it came from.

Today, through the tissue culture lab, Delbard produces about 1.5 to 2 million plants each year, which include 800,000 to 1.5 million rootstocks, according to Jean-Paul Reynoird, Delbard’s research director. Of the 300,000 fruit trees that are annually produced, two-thirds are for the retail garden centers and one-third for commercial growers. Many of the retail trees are sold in containers or pots.

In Europe, there has been a strong backlash from consumers regarding the development of genetically modified organisms by inserting a selected gene into a plant for disease or insect resistance or other traits.

The research and development arm of Delbard is using a process call "regenesis" to create new genotypes. This involves using irradiation to force mutations from tissue culture material. Lab technicians then regenerate a bud from the irradiated cells.

"Hopefully, we can change a few characteristics of the genes and find new genetic material from known genotypes," he said, adding that they are working closely with the National Institute for Agricultural Research (INRA).

Breeding program

Delbard was the first in France to initiate a breeding program for disease-resistant apples and is now breeding second-generation resistant varieties.

Seedlings that survive the screening process in the nursery greenhouse are planted in the field for two to three years. Only one tree per genotype is planted in the field. "We don’t treat for diseases in the test orchard or have a back-up in case it dies," Reynoird said. "Our goal is for disease resistance, so it either survives and goes forward or doesn’t."

Taste is a major factor in the selection process. Delbard uses three to four teams to taste the fruit in the orchard at harvest. Fruit is also kept in storage and sampled after time in storage. "Sometimes, it turns into a global war about which selections to keep when we go through the selection process," Reynoird said jokingly.

Delbard is working to set up a network of field trials and experiments in other areas for selection evaluation that involves the entire process, from harvest to packaging to marketing.

Each tree in the experimental orchard has a barcode for identification and has been located with a Global Positioning System (GPS).

Selections that make the third level are planted next to Fuji and Braeburn for comparison. At the third level, 40 to 50 trees of each selection are planted for evaluation. At this stage, Delbard involves the National Institute for Agricultural Research and the Technical Research Center for Fruits and Vegetables to help evaluate selections.

Reynoird said that only about 20 selections out of 2,000 hybrids will make it to the third level.

In the Delbard pear breeding program, fireblight resistance is the primary goal.

For a satellite view of Delbard Nursery and orchards, visit www.maps.google.com and type in the coordinates 46.29945N, 2.76535E and 46.29944N, 2.77644E.